1. Field of the Invention
The present invention relates to a protection circuit configured to prevent electrostatic breakdown, and particularly to a protection circuit employing a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).
2. Description of the Related Art
A semiconductor integrated circuit includes pads which allow signals to be input and output. When a static electric charge or surge noise is applied to such a pad, in some cases, it affects the reliability of the circuit components included in the semiconductor integrated circuit. In order to solve such a problem, a protection circuit employing a Zener diode or the like is provided to such pads.
For example, with an arrangement in which a positive voltage signal is transmitted to such a pad to be protected, a protection diode is arranged such that the cathode thereof is connected to the pad side and the anode thereof is connected to the ground terminal side.